ER-associated CTRP1 regulates mitochondrial fission via interaction with DRP1

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• C1q/TNF-related protein 1 (CTRP1) is a secreted protein linked to metabolic and cardiovascular diseases.
• The precise cellular functions and localization of CTRP1 remain largely unknown.
• Mitochondrial morphology is crucial for cellular health and is regulated by ER-mitochondria interactions.

Purpose of the Study:

• To elucidate the cellular roles and localization of cytosolic CTRP1.
• To investigate CTRP1's involvement in mitochondrial dynamics and morphology.
• To understand CTRP1's contribution to metabolic and neurodegenerative disorders.

Main Methods:

• Immunofluorescence microscopy to determine CTRP1 localization.
• CRISPR-Cas9 gene editing for CTRP1 knockout and depletion studies.
• Analysis of mitochondrial morphology (elongation, fission) and DRP1 recruitment to mitochondria.

Main Results:

• Cytosolic CTRP1 localizes to the endoplasmic reticulum (ER) membrane.
• CTRP1 deficiency leads to mitochondrial elongation, indicating defects in mitochondrial fission.
• Ablation of CTRP1 impairs DRP1 recruitment to mitochondria and disrupts ER-mitochondrion interactions.
• CTRP1 inactivation-induced mitochondrial defects are linked to apoptotic resistance and neuronal degeneration.

Conclusions:

• Cytosolic CTRP1 functions as an ER transmembrane protein and a key regulator of mitochondrial fission.
• CTRP1 plays a critical role in maintaining mitochondrial morphology through ER-mitochondrion interactions.
• These findings offer novel insights into the pathogenesis of metabolic and neurodegenerative diseases.